The Crazy Ivan was a maneuver in a twin engined vessel that could create a spinning motion on the ship. By having one engine running reverse and another running forward, the ship could effectively spin around quickly. This maneuver only functioned on vessels that have their engines mounted on axis from one another.
The Crazy Ivan maneuver was a last ditch tactic for crews of Firefly class ships used only when the alternatives were much worse—which was not very often. The crew of the Serenity executed a Crazy Ivan to escape from a larger and better armed ship, controlled by the savage and cannibalistic Reavers.
This maneuver relied on a Firefly class ship's ability to rotate its atmospheric maneuvering engines in mid-flight. First, both engines were oriented as normal, with the ship flying forward. Then, one engine cut off and rotated 180 degrees, then resumed firing. One engine was situated normally, and one was backward with both firing at full force. This allowed the Serenity to rotate much more quickly than normal and double back to face its pursuers. The crew then initiated the space drive while still in the atmosphere, launching them away from the planet at speeds hazardous for anything less than traveling between planets. Also, since the main engine relied on a trail of plasma behind the ship, starting the drive within the atmosphere catalyzed an impressive explosion.
The Reaver vessel was an older model which did not possess rotating engines, so it could not repeat the Serenity's maneuver. It was forced to turn around in a traditional way, wasting considerably more time than the quarry. This did not factor in nearly as much as the fact that the Reaver ship was caught in the explosion and never seen again.
The Serenity's crew could only pull off a Crazy Ivan within an atmosphere. There was not enough secondary fuel (i.e. Oxygen) in the vacuum of space to sustain such an explosion. The same drive was routinely used in space with only a signature glow to indicate that anything happened at all.
Behind the scenesEdit
The term "Crazy Ivan" was borrowed from the Tom Clancy novel The Hunt for Red October, and is named for the maneuver performed by Soviet/Russian (hence "Ivan") submarine captains to check their baffles—an area directly behind a submarine's engines that can not be monitored with sonar due to engine noise. This area creates a perfect hiding spot for enemy ships, thus the need to periodically spin around and "clear the baffles". The suddenness of the turn (hence "Crazy") is also a good deterrent against shadowing for extended periods of time, because it might result in a collision.